1. Technical Field
The present invention relates to an intake sound introducing apparatus for introducing the intake sound of an engine mounted in a vehicle into a cabin.
2. Related Art
In recent years, there have been intake sound introducing apparatuses which introduce the intake sound of an engine mounted in a vehicle into a cabin for an enhanced sporty feel. For example, an intake sound introducing apparatus described in Japanese Unexamined Patent Application Publication (JP-A) No. 2009-030451 (“vehicular intake sound transmission device” in JP-A No 2009-030451) has a communication pipe, a vibrator, and a resonator pipe (“resonator” in JP-A No. 2009-030451). The communication pipe is branched out from the intake pipe of the engine, The vibrator is provided in the inside of the communication pipe, and vibrates with the intake pulsation of the intake sound propagating within the communication pipe. The resonator pipe is connected with the downstream-side end of the communication pipe, and formed so that its channel cross-sectional area changes monotonously from the upstream side toward the downstream side.
This intake sound introducing apparatus allows the intake sound to resonate at a desired frequency by means of the resonator pipe, thereby making desired sound louder and transmitting the sound into the cabin.
However, intake sound introducing apparatuses according to related art are not able to reduce unwanted high frequency components of the intake sound (for example, the valve noise of the engine, or intake sound transmitted at high speed). Consequently, unwanted sound is mixed in the intake sound transmitted into the cabin, which may make it impossible to transmit desired sound into the cabin.